


The Oldest Habits

by Anonymous



Category: Good Omens (TV), Good Omens - Neil Gaiman & Terry Pratchett
Genre: (and more than double), Double Penetration, Genderless Characters, Hemipenis, I made a lot of this up, Other, Plot What Plot/Porn Without Plot, Vagina Dentata, basically monsterfucking, genital switches and transformations throughout, not-quite-penis dentata, sex - freeform, so I don't know what to tag it
Language: English
Status: Completed
Published: 2019-06-14
Updated: 2019-06-14
Packaged: 2020-05-12 00:52:14
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,767
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19218280
Author URL: https://archiveofourown.org/
Summary: The oysters are an agreed-upon signal.  Once the main course is finished, dessert begins.Or: Crowley and Aziraphale ignore both human biology and reality.





	The Oldest Habits

**Author's Note:**

> A Big Warning: genitals appear, disappear, and change shape throughout the fic on both characters, and they both go from having none to having everything. I use male pronouns throughout for the characters, and use standard language for the genitals when they appear (cock, clit, vulva, etc). Penetration happens in many different ways. That's not going to be for everyone, so please click out if you need to.
> 
> This gets a little wild, and I'm not entirely sure how to tag some of the sex acts. I tried to mention things that might bother folks, but if I miss something, please let me know.
> 
> Snake!Crowley appears briefly at the beginning to flirt, but he is human when they actually start having sex, so no snake sex or bestiality. Except for the hemipenis, because I can't help myself.

“That was quite delicious. Should I thank you for it?”

“No, angel.”

Crowley was slumped in one of the two uncomfortable chairs that Aziraphale kept in the back room of his bookshop. Aziraphale had updated his furniture near the turn of the twentieth century, and admittedly, this chair was much more comfortable than the terrible seventeenth century one he’d had previously. Aside from the furniture, the bookshop was dim, dusty, and had the air of something that should smell bad, but miraculously did not. The windows were fogged with dust, and Crowley had been meaning to have a chat with Aziraphale about the stacks of books that kept encroaching on the small space. Humans called it “hoarding” now.

They tended to drink here more than Crowley’s flat, and they were currently enjoying a nice bottle of German riesling. But they rarely ate here. Aziraphale insisted humans could smell the food on the books, which Crowley doubted. But Aziraphale allowed it under certain circumstances. Crowley had brought oysters, and Aziraphale had been delighted.

It was how these nights always began. Crowley would offer to bring oysters, and Aziraphale would agree. They both knew what happened after.

He only ever watched Aziraphale eat them. Aziraphale always sucked the meat between his lips, then licked the salt and ice that edged the dark shells, taking his time with each one. He’d licked his fingers when he was finished too, the bastard. He was currently smiling his aggravating little smile behind his wineglass, giving Crowley the perfectly blank, angelic look of kind obliviousness.

“Don't thank me. Give in to temptation instead.”

“Temptation? Am I missing something?”

“Angel.”

“Yes?”

“You know what I mean.”

“I’m afraid I don’t.”

“You do this every time.”

“Are you trying to tempt me, Crowley?” His expression changed to perfect confusion. Crowley hated him. “You’ll have to be more direct. I don’t understand what you’re about.”

Crowley leaned forward and placed an elbow on the table, resting his chin in his hand and slumping further into the seat, studying Aziraphale through his dark glasses. He stared. Aziraphale understood damn well. But as he continued staring, and Aziraphale continued to look confused, he realized it was going to be one of _those_  nights.

“Liars go to Hell, angel.” He sat up, leaning in closer to Aziraphale, putting his hand on his thigh and his lips near his ear. “Sssso letssss cut the sssshit, sssshall we?”

At each sibilant _S_ , Crowley allowed himself a pause to let his tongue, significantly less human and more Tempting Serpent-like than it had been a moment ago, vibrate against Aziraphale’s ear. Lobe, then shell, then the sensitive skin of his temple, and directly inside. Snakes didn’t salivate, and Crowley found it necessary for this sort of thing, so he’d made his tongue slick and unnaturally hot for that final tease, letting a small trail of thickish saliva run down the edge of Aziraphale’s jaw.

Aziraphale, on good nights, had very sensitive ears. A condition he could ignore at will.

“Crowley, you know I’m not good with human metaphors.” He was frowning in stern disapproval now. “I told you, if you are trying some sort of demonic temptation, you will need to be more direct.”

Crowley looked at him over the tops of his glasses. He exhaled a needless breath, then vanished in a cloud of black smoke. A moment later, he was wrapped around Aziraphale, a large, black serpent straight from Eden, coiling around Aziraphale's body again and again, binding his arms to his sides and his torso to the chair, his long lower half trailing to the floor behind them. His large, nearly human-sized head hovered just in front of Aziraphale’s face. He still had his glasses on.

 _You know I could eat you alive. Swallow you whole._  Snakes couldn’t use language the way humans could, so this was murmured into Aziraphale’s thoughts, a low throb of sound and sensation and arousal, all of it he could muster.

It was effective, because Aziraphale closed his eyes and shivered. But he rid himself of the temptation like water off a duck’s back, there and gone again. A moment later, he opened his eyes and smirked.

“Was that supposed to be a seduction? I’ve told you before, you really should read more human poetry.  You lack imagination.”

Crowley responded by tightening himself around Aziraphale, hard enough that the chair creaked beneath him. Smooth black-scaled coils glinted in the dim light, and Crowley thought he looked quite fetching. He was squeezing tight enough to injure a human, though Aziraphale was choosing to be unaffected by it all, of course. Crowley could feel the smooth beating of the pulse Aziraphale didn’t have through the entirety of his body, the steady thump of it resonating through every part of him. That was Aziraphale’s doing, and it was at least something. But not much. Not enough to continue. Aziraphale was truly infuriating when he got like this. It forced honesty from Crowley, which really wasn’t his style.

_Don’t care how imaginative it is. I'd consume you. You know that._

“Well, I care. There isn’t anything arousing about the thought of being eaten. Anyone would agree.”

_Some humans wouldn’t._

“Crowley, I don’t care about… _niche interest_.” Aziraphale was growing more stern now. “Tempt me or don’t, but this isn’t working.”

At a thought, Crowley was smaller, a tiny black snake slipping inside the collar of Aziraphale’s starched shirt. He coiled around Aziraphale's neck for a moment, and was rewarded with Aziraphale tipping his head slightly back and swallowing - the rippling scales of his serpent belly tickling the (presumably, if Aziraphale was at all merciful) sensitive skin of his neck. Crowley gave a brief squeeze, then dove headfirst into the warmth of Aziraphale’s shirtfront.

He meandered across Aziraphale’s collarbones, working his way down his chest. He coiled around one of Aziraphale's soft tits, then flicked his tongue out, still very warm and wet, tickling the nipple he found there.

The size of Aziraphale’s nipples was never consistent, nor the number. Tonight, it looked as if there would be two, and they were very small. When Aziraphale didn’t move after two or three flicks of Crowley’s tongue, at a thought, Crowley made the skin _very_  sensitive, then tried again.

He was rewarded with a surprised, breathy outburst from Aziraphale, a vocalization that Crowley could feel through his entire body. He laughed into Aziraphale’s thoughts, then teased again. There was another quiet gasp, this one less surprised and more resigned, then a gentle hand cupping him through the waistcoat and shirt.

“You _demon_ ,” Aziraphale managed, his voice cracking as Crowley’s tongue tickled him again. “None of that, now.”

Crowley tried one more time, but Aziraphale had miracled away his sensitivity. If he'd had vocal cords, Crowley would have grunted, but, more determined now, he moved lower, dipping below Aziraphale’s belt and into his pants.

To find nothing.

On better, more welcoming nights, there would be a pubic mound and labia, warm and wet and inviting, and Crowley, in his small snake body, would make himself comfortable. On nights when Aziraphale was being difficult, there might only be the warm fold between thighs, leading to the sensitive pucker of skin hidden within the angel’s tempting, heavenly ass.

Tonight, there was nothing there, only flat, warm skin between Aziraphale’s thighs. Denying him any sort of entry.

Another cloud of black smoke, and Crowley was again as human as he could be, straddling Aziraphale’s lap and fully clothed in his usual black suit. His hands were braced on the back of Aziraphale’s chair, his forearms pressing against the his shoulders.

“ _'Ziraphale_ ,” he complained. “You gotta give me something. If you don’t want it, just say so and I’ll leave.”

“Oh, I didn’t say _that_ ,” Aziraphale replied. “But I do keep telling you to be more direct.”

“I-want-to-have-sex-with-you.” He enunciated every word, clearly and loudly. Aziraphale at least watched his mouth as he did, but that was the only reaction.

“Then do so, Crowley, and stop being ridiculous.”

Aziraphale managed to say this with the same pinched expression and tone of voice that he used when his scone was stale. Crowley glanced around again. Still the dirty bookshop, the piles of musty books, and the little table they’d just eaten on.

“ _I’m_ being ridiculous. Why do you always say no to my place? I have a bed, angel. We don’t have to fuck where we eat.”

“Vulgar. I am not going to a demon’s lair to be tempted. If you are opposed to this arrangement, we can use the floor.”

“The floor. Really.”

“We are not having the bed debate again.”

The bed debate really was tired. Crowley had been trying to tempt Aziraphale into sleeping for millennia. The progressive improvements to human sleeping arrangements were less for the humans than they were for Aziraphale.  Though Hell had certainly appreciated Crowley’s dedication to sloth.

Crowley still wasn’t sure where any of this was going. “Aziraphale-”

In a rush of chill, Crowley found that both of their trousers had been miracled away. He glanced into Aziraphale’s face, verifying that he was still putting on airs of patient suffering, then went back to the matter at hand.

There were many ways to proceed, and Aziraphale never helped at the beginning. The options available to them should have made things easier, but Aziraphale also had strong opinions about what was and wasn’t _good_ , and they tended to change each time they did this. The Trouser Miracle had taken Crowley by surprise, so he was currently as bare and neuter as Aziraphale, who had at least spread his thighs slightly further apart.

Experimentally, Crowley reached between them. His fingers encountered the vulva he’d been expecting earlier, magicked there himself now. It was dry, freezing to the touch, and lacking a clit, which was Aziraphale being difficult again. He rolled his eyes and made it wet and warm, and ran his thumb gently, nearly reverently, over the clit as he slid his first two fingers inside.

At a thought, Aziraphale could be loose and slick, dripping onto Crowley’s hand. But foreplay was mostly pointless, as they could control the level of each other’s pleasure as much as they liked at any time. Aziraphale had an infuriating habit of triggering a low-level orgasm in Crowley to end frivolous debate. He also had little patience for foreplay, so this was entirely for Crowley.

He leaned forward, settling his forehead against Aziraphale’s shoulder as he slipped his fingers in and out slowly, stroking faster with his thumb, mollifying Aziraphale with curls of lazy pleasure that resonated slowly between them. Because the angel wasn’t completely heartless, Aziraphale’s hands stroked up Crowley’s back and pulled him closer.

Crowley, not being honest, would never admit that he enjoyed this close intimacy just as much as what came after. Aziraphale only ever let him close for this, and being close to Aziraphale was...

Well. Heavenly.

But Aziraphale was always greedy and ready for more. Crowley pushed a third finger inside him, pushed deep, then pressed hard upwards, hard enough to shift Aziraphale, letting more pleasure flow from his fingertips and up through Aziraphale's body, heat and warmth and tightness. He slid his damp fingers out and back, along the sensitive skin behind the vulva and back further, and found the pucker of skin he was expecting there, inside Aziraphale's now-present and very pert ass. He turned and grinned into Aziraphale’s neck, allowing his suddenly long, pointed teeth to scrape against his pulse point.

“How are you feeling about both tonight, angel?” Crowley pushed his index finger inside again, and at a thought, Aziraphale's ass was slick and ready. He withdrew, pushing two fingers inside, then a third.

“Both?”

Crowley leaned back, smirking as he reached down to grip himself. Sometimes, this part was fast and straightforward. But if Aziraphale was going to be difficult, so was Crowley.

Crowley, as a demonic snake, was entirely sexless, but the novelty of the Earthly snake penis had never grown old. So, of course, he had two cocks now, situated between his legs with one slightly further forward than a human penis would be, and the other taking the place of the sensitive skin behind it. No testicles - those were human, and only got in the way. Each organ was a pale pink, and because Crowley was feeling particularly frustrated with Aziraphale tonight, the tight, thin skin was covered with tiny white barbs, not quite sharp to the touch.

They hadn’t done this in a while, not with the barbs. Aziraphale finally looked impressed, a smile spreading across his face.

“Oh. _Both_.”

Double penetration wasn’t easy to manage in a chair, but they'd long grown used to it, and after all, it didn't really matter what the chairs were meant to look like. The back of the chair tipped back, the legs grew taller, and the seat grew longer as Crowley stood and Aziraphale slumped further back, still wearing his ridiculous jacket and waistcoat and watch chain, grinning beneath his tumble of blond hair. Crowley vanished all his own clothes but his dark glasses and his watch, then carefully positioned himself between Aziraphale’s thighs, holding them up to give himself a better position as Aziraphale gripped the bottom of the chair.

He found both entrances easily enough with both cocks. The human parts that Aziraphale was currently using weren’t quite suited to this, but it still worked. The spiky barbs on each penis caught and slipped past Aziraphale’s rim and the soft edges of his labia as Crowley slid inside him. Aziraphale could make this as easy or as hard as he liked, but they both enjoyed each other hard and tight. Crowley allowed himself the extreme sensation of feeling each and every one of the soft barbs enter Aziraphale, and how they pressed inside, how soft he was, how tight.

Crowley began panting, overstimulated and slightly dizzy, as he pushed himself further, not pausing until he had a full seat. Aziraphale was beginning to look affected too, a slight blush on his cheeks, his head tipped back, eyes closed and legs spread, fingers still gripping the seat.

Crowley slid himself out fast, and the sensation was almost too much twice over. He dialed everything down, still letting himself feel it, as he began moving his hips more regularly, Aziraphale slick and tight and warm.

When they tried double penetration, one of the two places they came together was always better than the other, though both could be made to feel similar. But today, Aziraphale's tight ass was beginning to make him impatient, too tight, catching too firmly on the barbs of his penis and slowing everything down. At a thought, the hole was less tight, but he knew Aziraphale felt the same frustration.

He was a moment away from simply vanishing the barbs on that cock, but was surprised when the tight ass turned into a second vagina. Crowley gasped, unused to a change mid-thrust. His eyes shot open, and he stared at Aziraphale in disbelief.

“Well?” Aziraphale said, somehow managing impatience. “Get on with it.”

He flexed muscles that he hadn't had before, flexed them in a way that shouldn’t have been possible, letting sensation ripple down the length of both Crowley’s cocks, along the very sensitive barbs covering his skin. Though Crowley tried to keep quiet (because Aziraphale didn't like it, and he’d be likely to shout encouragement, which was too close to worship and Forbidden), he allowed himself a loud moan, slumping forward as Aziraphale flexed the muscles again, this time with more heat and pleasure.

Crowley, regretting it immensely, dialed his own sensation back, then began fucking Aziraphale more fervently, faster, letting the slick, hot tightness of him be enough without the sensation.

He tried to turn the tables, letting each point on his dick be its own feeling - like a thousand points of pleasure inside Aziraphale. It worked, and he was rewarded with another small moan from Aziraphale, who slid further forward and involuntarily tightened in a more mundane way. Crowley paused, smirking.

“Like that, did you?”

Aziraphale arched his eyebrows. “Too much, Crowley. Harder, and more single-minded this time.” At Aziraphale’s words, the second set of everything disappeared, and Aziraphale leaned back, more comfortable and satisfied. “There. Simple is better, don’t you agree?”

The small barbs on Crowley’s cock disappeared, and Crowley shrugged, more than willing to go as fast and as hard as Aziraphale wanted. Sitting up straighter, Aziraphale wrapped his hands around Crowley’s ribcage, stroking near where Crowley's nipples should have been with his thumbs.

“Is it better, angel?” Crowley asked, slowing down and shifting his grip on Aziraphale’s thighs, focusing on threading more sensations of pleasure through his body. Sometimes this was all they needed.

“Whatever you like, Crowley,” Aziraphale replied softly.

It was so different from his usual affected aloofness when they did this, almost tender. Crowley gasped and slowed, but made his thrusts harder, causing the legs of the chair to squeak and groan, grunting and panting with the effort, trying to make it as good for Aziraphale as he could. Aziraphale responded, making himself more slick and tightening himself around Crowley. Aziraphale was damp between his thighs, and Crowley considered stopping and letting his tongue do more work, licking that divine offering from between Aziraphale’s legs.

On his next inhale, he found that he had unexpectedly developed something like gills along the smooth length of his cock - small slits that sucked the inside of Aziraphale. As he had been attempting to pull air into his body, he choked, somehow still coughing, the blood rushing to his head and his chest tightening from the effort of breathing fluid and soft skin instead of breath.

Aziraphale chuckled softly, and Crowley realized it had been a trap. Of course he’d noticed Crowley was breathing, the little bastard. Crowley forced himself to stop breathing, but still used his cock to suck on the inside of Aziraphale as he rolled his hips, and began moving again still slowly, still as hard as he could. Crowley couldn’t taste him this way, which was a shame, but Aziraphale seemed to enjoy it all the same, pulling himself tighter to Crowley and moaning appreciatively into his chest.

“Angel,” Crowley tried. He always wanted to tell Aziraphale how… this was between them, how it felt to him, but all the adjectives he could think of were too nice. And he knew if he was plain about what he wanted - tasting Aziraphale, feeling him, touching every part of him slowly and reverently - Aziraphale would stop everything. Though he was a stickler for being very direct, he still didn’t want to hear any of that out loud, and if Crowley said it, it would come out all wrong.

And besides, it would be too close to an act of worship, no matter how vulgar he was.

So he tried to communicate with just his body, sucking at the inside of Aziraphale, finally getting rid of Aziraphale's damn jacket and shirt and taking him into his arms, pulling him closer, angling him just so, and fucking him as hard as he could.

Aziraphale gripped him tightly for a solid minute, but he was changeable during sex, and never liked the same thing for long. The noises soon stopped, and Crowley could tell he was dismissing the arousal once again.

“Cruel,” Crowley tried, still focused on not breathing, trying to keep his voice as steady as possible. “Just cruel.”

“Isn’t that more your side?” Aziraphale answered brightly, sounding as unaffected as he could possibly be with Crowley balls deep inside him, though neither of them had remembered the scrotum.

“It originally came from upstairs, didn’t it?”

“Perhaps,” Aziraphale answered, sounding thoughtful. “Though I think you, being a demon, would know better than to accuse an angel of cruelty.”

There was a scraping sensation against Crowley’s dick as he pulled out for the next thrust, and it wasn’t until he pushed in again that he recognized it as the blunt edges of teeth, several rings of them. Nothing hard, nothing painful, but the suddenness of it startled him, and in the moment it took him to register the new sensation, Aziraphale bore down slightly.

“That-” Crowley began, beginning to pull himself out-

Only to find that he couldn’t. The warm tightness of Aziraphale pulled at him as he withdrew, enveloping him as he pulled out of his body. Aziraphale stood, and Crowley looked down to where they were joined, trying to process what he was seeing. His cock was sheathed in a very phallic appendage, large and pale and thick and still part of Aziraphale’s body. Muscles rippled, and heat and arousal pulsed through Crowley again.

“ _Angel_ ” he tried, and his voice came out slightly weaker than intended, more desperate.

“Yes?”

This time, it was Aziraphale who began thrusting, rolling his hips and pulling the fleshy appendage along Crowley’s dick. It felt like a mouth, like Aziraphale was swallowing him. There was only one row of teeth now, brushing the base of his cock, and the muscles rippled and pulled as Aziraphale found his rhythm.

“Angel, _what are you doing_ -”

Aziraphale paused. “You accused me of being cruel. I thought I would try something nicer.”

“Where did you learn this?”

“I didn’t learn it anywhere.” He made a slightly disapproving noise, emphasized by another swallowing flex around Crowley’s cock. Crowley shivered. “It’s simply that you lack imagination. All demons do. Haven't I said so before?”

“Not the time for this.”

“No? Well, you were the one who brought it up. Always so talkative.” He still had that slightly disapproving tone that was meant to imply he wasn't enjoying this, but he at least looked more affected than he had before. His face was fully flushed now, and his skin felt hot beneath Crowley’s hands where he gripped his waist, feverish and burning. Crowley wouldn’t be able to look at him much longer, and he drank the sight of him in now, the quirk of his lips, the way his hair still looked the same even in the middle of sex.

“I’ve told you before about speaking out of turn when we do this.” Aziraphale’s hand came up to Crowley’s mouth, covering it with a palm as he thrust forward again. Crowley closed his eyes and moaned, allowing his lips to part and his tongue, more human now, to taste Aziraphale’s skin. It was still salty from the oysters. Aziraphale shifted, and his two middle fingers pushed inside Crowley’s mouth. Crowley sucked them gratefully, this time tasting the wine too, which Aziraphale hadn't dipped his fingers into. He suckled, licking between them, and Aziraphale pushed farther inside.

And farther. They grew and lengthened, turning into something soft and firm that pushed its way down Crowley’s throat, then shifted and thickened. Crowley’s eyes flew open, and he attempted to make a sound, but Aziraphale only smiled, looking into his eyes as he flexed his new appendage, pushing into Crowley’s throat to the same rhythm that he pulled himself off and on Crowley's dick.

Crowley remembered not to breathe, forced himself to remember that he didn’t need to choke, but this was too much again, and he felt himself building to orgasm as Aziraphale pushed himself inside him and pulled against him, sending out the perfect waves of heat and tightness and pleasure. Crowley felt his knees going weak, and he gripped Aziraphale’s shoulders, content to let him have his way.

He always did, anyway.

He wouldn't last much longer, and Aziraphale knew it. Crowley was pushed back onto the tabletop, which changed to suit their needs, the dishes and glasses vanishing lest they make a mess of the books nearby. Aziraphale’s hand never left Crowley’s mouth as he climbed on top of him, bracing himself above Crowley with his elbow and knees, smiling benevolently down on him. Crowley was lost, lost, lost, staring into the blue of Aziraphale’s eyes and memorizing his expression while he still could.

Both their genitals disappeared for a moment, along with all the sensation of pleasure between them. It was like having a bucket of cold water thrown at him. He made a sound deep in his throat, his hands squeezing Aziraphale’s side, but Aziraphale only blinked.

A moment later, there was something new. Aziraphale pushed himself inside Crowley with something slightly too thin and firm to be a real human cock, but was close enough at this point in the evening. Since Aziraphale was currently the one performing miracles, and Aziraphale was nothing if not constantly cruel, he’d chosen the tighter, firmer feeling of Crowley’s ass as an entrance. Crowley was slick and hot and ready for whatever Aziraphale wanted, anything. Crowley knew that Aziraphale knew. And it meant something to him.

Aziraphale began rocking his hips, using the slow, firm thrusts that Crowley preferred, his fingers finding Crowley’s hair and combing through it. Aziraphale had positioned them just so, and had given Crowley the sensation of a human prostate, stroking firmly again and again with whatever was inside him.

Crowley closed his eyes and moaned around the firm, large intrusion deep in his throat, which was motionless now as Aziraphale concentrated and maintained whatever magic he was currently performing. And it was perfect, as it always was between them. Their chests and stomachs slipped together, Aziraphale's skin growing hotter and hotter. With a thought, Crowley slicked their skin, making them slide together. Aziraphale gasped suddenly, and the appendage down Crowley's throat disappeared as Aziraphale braced his hand next to Crowley's head.

Aziraphale was too turned on to feign indifference now. His hair had gotten slightly longer and more tousled, as it always did at this point, though Crowley had never determined which of them did that. Aziraphale's eyes were screwed tightly shut, and the perfect line of his teeth was just visible between parted lips.

“Angel,” Crowley tried, nearly there, close, so close. “I need…”

The fucking was never quite enough, not when there was only one part involved between them, and he only needed a little more to push himself over. He could do it himself - imagine himself a cock to squeeze, a clit to slide his fingers against and underneath.

But he wanted Aziraphale to do it.

“Aziraphale.”

But Aziraphale was beginning to lose himself as he pushed closer and closer to his own climax. When Aziraphale was close, he grew less concerned with looking human, and lost control of his appearance. Crowley loved it, loved watching the well-composed Aziraphale forget himself. Aziraphale's eyes opened at the sound of his name, still clear and blue and fixed on Crowley with singular focus. Another set of hands and arms appeared as he shifted himself back, using two hands to grip Crowley’s thighs and two more to push his shoulders back as he lifted Crowley’s hips and began to fuck him in earnest.

Aziraphale was also growing larger, both over and inside Crowley. His hands engulfed Crowley's shoulders and thighs as Crowley grew tighter around the thickening appendage inside him. Crowley enjoyed the sensation of getting smothered and torn apart by the angel, though neither of them would actually let it come to that. 

While humans had been made in the image of God, that was not true of angels and demons. The angelic form was beyond the comprehension of anything but celestial beings, and there was nothing really human about it at all. It was fluid and terrible, not fixed in any particular plane of reality. Crowley watched as humanity slid away from Aziraphale and he took a form not even the angels in Heaven used anymore - his true self, the one he only ever showed to Crowley.

As Aziraphale focused on Crowley and their mutual pleasure, sound and awareness fell away and left only sensation, the angel inside him and around him, his hands gripping Crowley. Aziraphale's hair grew even longer and changed into that particular shade of silver and light that only exists in Heaven, a color that Crowley only ever saw on Aziraphale now.

Crowley, a demon, was not meant to look upon an angel in this form. It was one of the weapons angels possessed to fight demons, a final and terrible solution that was difficult to combat without preparation. The sight of Aziraphale’s face as it became less and less human - as he forgot what eyes looked like, or how many lips he should have - was painful on a spiritual level, forbidden. Crowley felt blood run from the corners of his eyes, and he closed them and turned his face away, moving his hands to grip Aziraphale's wrists where he clutched at his shoulders.

There was less motion and more sensation now as they experienced a unification of being that did not happen with more mundane sexual intercourse. It was not an act committed lightly, not even demon to demon or angel to angel. They’d been doing this together for thousands of years, and yet Aziraphale had only just begun to acknowledge the meaning, and what it made them.

When they were both in this state, Aziraphale was always better than Crowley. Crowley’s methods of sexual intercourse, unfortunately, were necessarily simple. To lose himself as Aziraphale did, to let himself forget his human shape, would mean reverting to his natural form, which was a sexless snake.

Not all angels had been Principalities. He’d only ever been a snake, Eden or humans or no. So he had to restrain himself more than Aziraphale did. When it came to this sort of thing, when they got to this point, it had to be Aziraphale that finished for both of them.

Aziraphale was close, Crowley knew. He felt another pair of hands grip his ankles, pulling him, holding him, pressure building around them in a way that had nothing to do with the reality in the back of the bookshop. The hands were just for him - he loved being held, touched all over by Aziraphale. And he couldn’t look at him now, could feel himself heating up from being a demon too close to an angel in full glory, the fire of Heaven licking along skin that he hadn’t remembered until just now.

Aziraphale shifted to sit on top of Crowley, and their genitals changed shape again so that Crowley was inside Aziraphale, too hot, too much, and Aziraphale was flexing his thighs, riding Crowley to what came next. Crowley, with the last of his concentration, gave them two more sets of genitals so they could both be inside each other, but with Crowley penetrating Aziraphale twice, because he was damned, and it hurt, and this was how he hoped to meet his end, with Aziraphale in and around him as much as he could be, with the perfect tightness and heat and sensitivity between them in the most intimate way two beings could experience.

Crowley felt a slight brush of air as Aziraphale released his wings. He dared not look at them. They were moments from the end. He shifted and released his own beneath his back, and felt the touch of dozens of fingers in his feathers, probing the sensitive skin beneath. There wasn’t anything Crowley could do to match that, so he raised his hands and felt around Aziraphale's shoulderblades, where the wings met his body. Aziraphale had four wings when he wasn't paying attention, and Crowley slipped his fingers beneath and between them.

Aziraphale leaned down, pushing something like a mouth down against Crowley’s lips. Aziraphale kissed him, and Crowley let himself sink into the sensation of the angel’s not-quite-mouth, exploring blindly with his snake tongue and snake teeth, and he felt Aziraphale probing and sucking with a thought. Crowley kept his eyes closed. This part was always so dangerous.

“Crowley,” Aziraphale said in the celestial language, which wasn’t sound and words but something more profound, something that always gave him the burning uncanny sensation of being spiritually flayed, bringing the reality of what they were doing back to Crowley's body. He felt blood trickle from his ears and from the corners of his mouth, felt the same from the not-mouth pressed to his, the ichor they both shared, sweet and acid.

“Crowley. Say it.”

Crowley clenched his eyes tighter and made a sound with the human vocal cords he still possessed. He knew what Aziraphale wanted. It was forbidden, he told himself it wasn't true, he couldn’t say it aloud, it _hurt_.

“Crowley.”

But when an angel gave an order, one was compelled to answer.

“I love you, angel. You know it.”

Saying it filled his tongue with a crawling bitterness, pain cascading down the rest of his body. But it was enough. There was a sigh in that all-around-celestial voice, and they finished, the cores of their beings intertwining in a way that should have been impossible, should have unmade them both. And maybe it had, the first time, and they’d been made into something different. That would explain a lot. About both of them.

This part was always so messy, and so many sensations were lost to Crowley when it happened. He couldn’t see with human vision, the pain scourged him of feeling. There was pain, and the taste of ichor in his mouth.

And pleasure. And Aziraphale. And too much, and more, and more than that. The moment always felt like it could stretch on forever, the in-between after they finished.

But Aziraphale, always a bit of a bastard, was the one that brought it to a neat end every time.

In a flash, Crowley opened his eyes to the bookshop. Aziraphale was sitting at the small table in his white suit and waistcoat, hair slightly mussed, back straight, scrutinizing Crowley. Crowley was slumped over the table, also fully clothed. Apparently, he'd knocked over an empty wineglass at some point.

“Crowley, really. You need to learn to control yourself," Aziraphale said, smirking as he straightened a cuff.

Crowley reached up and felt a trickle of blood at his mouth. A horrible sensation that felt like bitter bees still marched across his tongue. He really, really shouldn’t have said that. Especially not for this smug asshole.

“Why do I even bother,” he muttered, compulsively clicking his tongue inside his mouth.

Aziraphale, unruffled, righted his wine glass and poured fresh for both of them. “Your nature, I suppose.” He carefully set the bottle back onto the table, and raised his glass, peering over the rim. “You really should know better by now. I’m an angel. I’m immune to temptation.”

**Author's Note:**

> The starting point for this fic was definitely [this thread on Twitter](https://twitter.com/brawlite/status/1138614199972696066), which is amazing.


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